#define  _CRT_SECURE_NO_WARNINGS
class Solution {
public:
    string modifyString(string s) {
        for (int i = 0; i < s.size(); i++)
            if (s[i] == '?')
                for (char c = 'a'; c < 'z'; c++)
                    if ((i == 0 || c != s[i - 1]) && (i == s.size() - 1 || c != s[i + 1]))
                        s[i] = c;
        return s;
    }
};